Conventionally, many pneumatic tires are known that are provided with a sealant layer having an adhesive/fluid sealant fluid coated on an inner circumferential surface of a tread portion of a pneumatic tire. When such a tire runs over a nail or the like and is punctured, the pneumatic tire self-seals by the sealant fluid flowing into a puncture hole after the nail falls out due to centrifugal force.
However, because the sealant fluid has fluid properties, centrifugal force during high-speed running causes the sealant fluid to accumulate in a tire center region of a tread portion inner wall surface in a tire width direction, resulting in insufficient sealability in shoulder regions. This results in a problem of puncture sealing functionality not being displayed.
In order to solve such problems, pneumatic tires in which the sealant fluid is impregnated into a porous material having interconnecting cells, such as a sponge, or the like, and this porous material, into which the sealant fluid is impregnated, is attached lamellarly to an inner circumferential surface of the tread portion are proposed in the prior art. With this sort of pneumatic tire, not only is the problem of reduced puncture seal performance caused by localization of the sealant fluid in a tire center region of the tread portion during high-speed running resolved, but because the porous material having interconnecting cells has sound attenuation properties that absorb resonance noise generated in tire cavities, a benefit of noise prevention performance is also displayed.
However, regarding the noise prevention performance of the aforementioned conventional pneumatic tires, a significant amount of a cubic capacity of the interconnecting cells is blocked due to the sealant fluid being impregnated into the porous material. Therefore, noise prevention performance is not being sufficiently displayed.